1. Field of the Invention
The present invention relates to a driving instrument for driving a fixing means, preferably a spike for fixation of fractures in the neck portion of a thigh-bone, whereby said fixing means comprises a sleeve, a pin provided in the sleeve and a driving device connected to the sleeve for driving the end portion of the pin out of the sleeve via a side opening therein and into a certain part of surrounding bone material.
2. Discussion of Related Art
A driving instrument of the above type is disclosed in U.S. Pat. No. 2,631,584, but this prior art driving instrument does not provide for quickly and safely orienting the spike such that the opening in the sleeve of the spike is positioned exactly in a predetermined position relative to the surrounding bone material. According to this publication the spike is instead oriented before driving such that the opening is aligned substantially correctly whereupon the spike is driven into the bone without providing it with a predrilled passage which facilitates the driving. Adjustment of the spike after driving to correct the position of the opening is very difficult because, the instrument must be separated from the spike sleeve in order to determine where the opening is positioned. This procedure tends to prolong the operation time in an unacceptable way. Another problem delaying the operation and complicating the positioning of the spike arises in that the spike may be rotated only in one direction by the attached instrument. The instrument loosens from the spike instead of rotating it if rotated in the opposite direction.